For those who aren’t comfortable poking around in Device Manager, utilities like DriverDoc can scan your hardware and pull the exact Billionton/Broadcom match for your specific OS version.
Broadcom BCM2035B is an older Bluetooth 1.1/1.2 single-chip transceiver typically found in older laptops (like HP, Acer, or Dell) and USB dongles. Finding modern, official drivers can be difficult because Broadcom has largely moved its support to its Customer Support Portal Driver Identification bcm2035b usb bluetooth driver